Updated: Sep 29, 2020
Based on 'Rock glazes of NZ'
Sample 1: Semi-schist
A light greenish-grey rock showing a pronounced platey structure The surface shows tiny glittering flakes of mica. This and similar rocks are widespread in the South Island, e.g. parts of Malborough and North and Central Otago
Essentially Quartz sericite (secondary white mica) epidote and soda feldspar. Composition variable but with high silica( 65%-70%) and alumina.
Samples of fine-grained schist were located in the Kawarau Gorge, Gibbston Valley. These were gathered from roadside cuttings that were easily accessible. The Gibbston Valley has both grey and greenschist, which have fairly obvious distinctions in colour when wet.
Schist is everywhere throughout Central Otago these are mostly identified by colour, grey, green, pink, purple depending on the varying mineral content. Geotrips.org.nz is a great site geared up for adventures through the local geology and maps locations of exciting geology throughout New Zealand. Two spots on the site that mention schist are the popular tourist spots of the Kawarau Bridge and Arthurs Point, where the Shotover jet is based. Arthurs Point on the Shotover River and Tuckers beach close by have a variety of different coloured schist.
There are also pink granites in Skippers cannon and roadside cuttings along the Crown range road which I didn't explore due to snowfall.